“This is the place where people come to have their informal meetings over a coffee. I often say, if you were a lip reader, you could probably make a fortune walking through this place.”

The Engine Room

How did the historic City of London, the venerable square-mile district where England’s financial culture first arose five centuries ago, transform itself in just thirty years into one of the most dynamic and most iconic skyscraper skylines on earth? I learned how ona tour of the Square Mile with Peter Rees, the man who made it happen.

The Heron is blandly handsome as London skyscrapers go, compared to the nearby, and similarly whimsically nicknamed, “Gherkin,” “Walkie Talkie,” or “Cheesegrater” towers. But the three-year-old luxury building is exceptional in two respects. For one thing, it’s the first housing block since the 1970s to be located in the City, the compact, ancient financial center of London, also known as the Square Mile. For another, its few full-time residents include Peter Wynne Rees, who personally approved its construction — along, as it happens, with the Gherkin, Walkie Talkie, and Cheesegrater. As the longtime chief planner for the City of London Corporation, Rees is, arguably, the person most responsible for the stunning recent transformation of London’s historic core into one of the fastest growing centers of commercial development on the planet.

After a remarkably long tenure — nearly thirty years — Rees retired in 2014, but is still fiercely protective of what he calls “the engine room” — the economic hub of Greater London, the United Kingdom, and perhaps the world. (For now.) He’s been outspokenly critical of luxury apartments marketed to absentee owners who wire the funds from offshore accounts, notoriously describing such projects as “safety deposit boxes in the sky.” But on a recent tour of the district I discover he’s surprisingly skeptical of housing in general, given that most homes are empty during the day and dark at night. The City has neither the time nor the room for that.

“It’s a waste of land, which is in short supply here,” Rees tells me during our walk. “Cities can’t afford that degree of underuse.” He sees the City, above all, as a commercial reactor fueled by chance encounters and traded snippets of information — what he calls “the gossip.” Though accelerated by the financial deregulation in the 1980s, this heritage reaches back several centuries, starting with the founding of the Royal Exchange in 1571, spilling over into the Restoration-era pubs and coffee houses lining nearby Change Alley, and continuing to this day in the pocket parks and arcades he and his staff planned or protected. “People make places; places make gossip; gossip makes people money,” he explains. “And the City is especially well-designed to allow that to happen.”

Tall, lantern-jawed, and incisively critical, Rees is an intimidating yet solicitous guide to “probably the only point on the planet that has a 2,000-year continuous trading history,” he says, ever since “a couple of boatloads of drunken and sex-starved Romans ran aground in the Thames.” Strolling from The Heron, through the Barbican, to the Museum of London, we pass guild halls, remnants of Roman walls, and a hostof Christopher Wren-designed churches — all of which are off-limits to redevelopment. To make space for the museum, he notes, “we had to find a site that didn’t exist by building it over a roadway.”

In 1986, barely a year after Rees had arrived in his post as the Corporation’s youngest officer in its history, the City experienced the “Big Bang” — the deregulation of the London Stock Exchange and of British banking in general. The subsequent explosion in trading literally sent him and his staff back to their drawing boards. Polling a pair of property consultants on how much the floor space the City would need over the next decade, “one determined twenty million square feet, and the other said Well, it’s too late, you won’t be able to meet the demand in time, so none,” Rees recalls. “Being good planners, we averaged our data — so, twenty million or nothing? Okay, ten million — and we managed to create that over a decade. The City has grown by that much every decade since.”

Doing so has required rebuilding 80 percent of the Square Mile’s gross leaseable area, he estimates, a figure even more impressive in light of more than 700 “heritage buildings” — designated landmarks, in American terms, that cannot be demolished — and the strict limitations on development established by more than a dozen protected viewsheds of St. Paul’s Cathedral. With so many variables in play, Rees abolished all hard and fast rules for approvals, such as the conventional (and standardized) Floor Area Ratios used in New York and other U.S. cities (“Once they discovered atriums and building over roadways, it was completely shot”) and resolved to judge each building individually, on its merits.

More than the Gherkin and a glut of Christopher Wren churches, the City is the sum of its interstitial spaces.

Although this gave him unprecedented authority by American standards, Rees denies being much of a planner. “Planning doesn’t give you a kit of tools to do things in this country the way it does in the rest of the world,” he insists. “We can’t have master plans — we simply have a set of rules for things you can’t do.” Those rules are intended to limit real-estate developers from building out of context, relative to the City’s history and topography, which on his watch generally meant gradually hammering plans into shape until they fit his principles, rather than rejecting them outright at the start. “I always said to developers, you should come to see me at the back of the envelope stage,” he says. “Please make sure the architect doesn’t draw on the envelope first.”

One New Change is a case in point. The grey origami-planed shopping mall opposite St. Paul’s met with Rees’ approval after the architect Jean Nouvel strode into his office bearing a cardboard box rather than blueprints. Reaching inside, he told Rees, “I have to fly under the radar of St. Paul’s, so I appreciate my building must be invisible,” and produced a model of a B-2 stealth bomber. “It’s one of the few buildings where the architect chose the nickname,” Rees recalls.

Standing on its rooftop terrace, he points to the adjacent bar and notes with relish that when he began his tenure, the City’s pubs closed not long after the last suburban commuters had fled. Today, a new generation of bars and clubs remain open until early morning on the weekends, and for many young bankers, the line between business hours and after-hours has been erased. “They get the job to pay for the party, not the other way around,” Rees observes.

His exuberant embrace of nightlife as a development principle has been acidly described by the architecture critic Rowan Moore as “eroto-economics.” Rees’ critics argue he has projected his own preferences as an unapologetically gay bachelor onto the City, to the point where he once remarked that families make cities in general dull. But in his defense, merchant banking arose from the City’s pubs and coffee houses, where the gossip was at its thickest. He reiterates this point while we stop for cappuccinos in the atrium of the Royal Exchange, “the place where people come to have their informal meetings over a coffee. I often say, if you were a lip reader, you could probably make a fortune walking through this place.”

“One of the things that gave me the greatest pleasure over the years was increasing pedestrian permeability in the City, and increasing the amount of urban space,” he tells me. This wasn’t just a personal preference; it was also good business. Towers are excellent for stacking tens of thousands of bankers and insurers in a confined space, but they are a terrible means of collecting new information.

“In the American dream,” he says, perhaps thinking of Mad Men-era midtown Manhattan, “we would be locked in the office from at least 9 until 5. Of course, that’s a very inefficient way to do things, because when you’re trapped in your office, the only gossip you hear is the gossip of your friends,” he explains. “But you already know that. What you want is the gossip that you don’t know you want — it’s the chance encounters, the eavesdropping and overhearing things in the street, in the alleyway.”

Elevenses at the Lamb Tavern, where the gossip gets made.

To demonstrate, we cross the street and wind our way through Ball Court and St. Michael’s Alley, where City suits stand outside sipping lunchtime pints at the Jamaica Wine House and The George and Vulture. The former claims to be London’s first coffee house, frequented by Samuel Pepys (the original modern mobile worker), while the latter is virtually unchanged since its appearance in Charles Dickens’ The Pickwick Papers. “There’s an actual clubhouse in the center of the City where businessmen of all shades gather and gossip to this day,” Rees says, point at The George and Vulture. “You can just peek into the windows…”

Emerging from the rabbit’s warren, we head in the direction of 22 Fenchurch Street, better known as the Walkie-Talkie. Designed by the American architect Rafael Viñoly, and winner of the 2015 Carbuncle Cup for the ugliest building in the U.K. completed that year, the tower is famously bigger at the top than at the bottom, which many believe is a ploy to cheat its neighbors of their sunlight and air rights. This is an illusion, Rees insists. “I keep telling people: it’s not larger at the top than it is at the bottom; it’s smaller at the bottom than it is at the top!”

He and his fellow planners had forced Viñoly to taper the building at the base, as well as lopped more than a hundred feet off its proposed height. The building’s other great failing — that it focused the sun’s rays to a point that could melt cars — wasn’t the architect’s fault, but the value engineers’, who had eliminated Viñoly’s planned screens. “It’s always worth remembering every building is a prototype,” says Rees. “You only get one go at a building; you can’t build a full-sized model first.”

The remainder of our tour amounts to the City’s “greatest hits” compilation — the Gherkin, the Cheesegrater, and Richard Rogers’ inside-out Lloyd’s building, which I stutteringly compare to grain silos, or the Space Shuttle’s launchpad gantry. “It’s a laundry…for money,” Rees tartly replies. Rather than take a victory lap, he’d rather focus on their flaws. Swiss Re’s Gherkin — the Square Mile’s architectural Big Bang designed by Lord Norman Foster — dominates and thus dulls the plaza around it. The Cheesegrater’s half-hearted public space at its base is awkward at best, and Lloyd’s floats freely from the street, redeemed at ground level only by the adjacent bustle of Leadenhall Market.

In the wake of the Gherkin’s rapturous reception, Rees received inquiries from around the world asking how one plans an “icon.” “An icon is a third-rate Russian painting with very little artistic merit,” he reminds me, “which acquires religious significance because worshippers attribute it with mystical powers. It’s the public, not the artist. So, you cannot ask an artist or an architect to design you an iconic building. If you do, you’ll get a wacky building, which is not the same thing at all.”

We are at the end of the tour in the churchyard of St. Botolph’s, wedged between the towers of Bishopsgate and Liverpool Station. Rees is off to teach a class at the Bartlett — University College London’s architecture school — which he joined following his retirement in 2014. He has no successor; the City of London Corporation eliminated his position. (“The power of planning is waning,” he’d told me. “Central governments see it as an impediment on development.”)

Mindful of how lower Manhattan transformed into a residential district following 9/11, I ask whether he can ever imagine more towers like The Heron sprouting across the City, especially given the profit margins. “No, I think the City does need its special character,” he says. “I think it works better as a business district because it’s focused. It knows what it’s about. It’s an engine room. It’s only one square mile; you can have all of the rest of London to live in. People can even live close enough to walk to work in the City, or cycle. But you need an identifiable business district; you need the street where they only sell bananas. And this is the street where they only sell bananas.”

This essay was made possible with the generous support of the John S. and James L. Knight Foundation.